Researchers from the University of Surrey and Royal Surrey County Hospital have made a major breakthrough by treating bladder cancer patients with a type of common flu virus.The oncolytic ('cancer-killing') virus coxsackievirus (CVA21),has been found to potentially target, infect and destroy cancer cells in patients with bladder cancer. The results of the study was published in the medical journal Clinical Cancer Research.
The study involved 15 patients with non-muscle invasive bladder cancer (NMIBC). NMIBC is found in the tissue of the inner surface of the bladder and is the tenth most common cancer in the world with approximately 800,000 people each year diagnosed with the illness.
Current protocols for bladder cancer are not effective. Transurethral resection, an invasive and delicate procedure that removes all visible lesions, has a high tumour recurrence rate ranging from 50 per cent to 70 per cent as well as a high tumour progression rate between 10 per cent and 25 per cent over a period of two to five years. Another alternative, immunotherapy with Bacille Calmette-Guerin, a live bacterium used to treat bladder cancer, has been found to have serious side effects in 35% of NMIBC patients while 40% do not respond to the treatment at all.
In this breaking study, 15 NMIBC patients,7 days prior to prescheduled surgery to remove their tumours, received CVA21 via a catheter in the bladder. Examination of tissue samples post-surgery discovered that the virus was highly selective, targeting only cancerous cells in the organ and leaving all other cells intact. The virus was found to have infected cancerous cells and replicated itself causing the cells to rupture and die rapidly. Samples of urine taken from patients showed 'shedding' from the virus indicating that once virally infected cancer cells had died, the newly replicated virus continued to attack more cancerous cells in the bladder.
Normally tumours in the bladder do not have immune cells, preventing a patient's own immune system from eliminating the cancer as it develops. Results suggests treatment with CVA21 inflames the tumour causing immune cells to rush into the cancer environment, targeting and destroying the cancer cells. These tumours devoid of immune cells are known as 'cold' areas immunologically; however, treatment with the virus causes inflammation and immune cell stimulation to create 'immunological 'heat'. 'Hot' tumours in this way are more likely to be rejected by the immune system.
Results showed that following treatment with the virus, cancer cell death was identified in the majority of the patients' tumours. In one patient no trace of the cancer was found during surgery.
"Non-muscle invasive bladder cancer is a highly prevalent illness that requires an intrusive and often long treatment plans. Current treatment is ineffective and toxic in a proportion of patients. Oncolytic viruses Coxsackievirus could help revolutionise treatment for this type of cancer. Reduction of tumour burden and increased cancer cell death was observed in all patients and removed all trace of the disease in one patient following just one week of treatment, showing its potential effectiveness. Notably, no significant side effects were observed in any patient.This new protocol could transform the way we treat cancer and could signal a move away from more established treatments such as chemotherapy."said Hardev Pandha, Principal Investigator of the study and Professor of Medical Oncology at the University of Surrey, in a phone interview with Thailand Medical News.